Plasma Ropes ----- Help

[Dave Martin]

To any club using plasma ropes in place of steel.

Having read the benefits of this type of rope, several
UK clubs are interested in its use. One major obstacle
to this, is cutting it during a launch, in the event
of an emergency

So far the best methods appear to be an axe an anvil
type cutter.

Any slight imperfections on scissor, guillotine and
even the axe methods of cutting mean the rope does
not get completely cut through. Even though the equipment
cuts steel succesfully.

Various methods such as hot wire and laser beams have
been suggested, but with the way members treat club
equipment I suspect the life of such things would be
minimal.

What emergency cutting methods for plasma rope do those
who use it employ?

Thanks in anticipation

Dave Martin

[Sf760]

I understand that Skylaunch have developed a guillotine that cuts it very
nicely.

[Bill Daniels]

"Dave Martin" > wrote in message
...
> Various methods such as hot wire and laser beams have
> been suggested, but with the way members treat club
> equipment I suspect the life of such things would be
> minimal.
>
> Dave Martin
>
Why should a hot blade be fragile? The winch engine starting battery has a
lot of power to heat a robust blade very quickly. You only need to get the
blade to Spectra's 265F melting point - far below the blades melting point.
I would just mount the blade in a strong frame near the path of the rope and
push the rope against the stationary hot blade with a rubber block. If well
built, it should last nearly forever.

Bill Daniels

[tango4]

Surely a scissor type gulliotine would be more effective

Ian

"Dave Martin" > wrote in message
...
> To any club using plasma ropes in place of steel.
>
> Having read the benefits of this type of rope, several
> UK clubs are interested in its use. One major obstacle
> to this, is cutting it during a launch, in the event
> of an emergency
>
> So far the best methods appear to be an axe an anvil
> type cutter.
>
> Any slight imperfections on scissor, guillotine and
> even the axe methods of cutting mean the rope does
> not get completely cut through. Even though the equipment
> cuts steel succesfully.
>
> Various methods such as hot wire and laser beams have
> been suggested, but with the way members treat club
> equipment I suspect the life of such things would be
> minimal.
>
> What emergency cutting methods for plasma rope do those
> who use it employ?
>
> Thanks in anticipation
>
> Dave Martin
>
>
>
>
>
>
>
>

[Sf760]

Tried that, with a shiny new freshly sharpened scissor type guillotine, and it
didn't cut it, this stuff has very fine fibres which just bent around the
corners. even using heat-shrink sleeving to simulate a plastic coating, we got
the same results, you simply could not be sure of cutting the rope.

[Bob Johnson]

Dave --

Just thinking out loud here, always dangerous: nail guns, either
percussive, powered with shotgun shell or the like, or pneumatic with
air cylinder. Sorry, no blueprints available. Replace nail with blade
would be good.

Wondering about guillotines in general, I know it's always good to have
one, but has anyone in earshot actually used one? If so, what were the
circumstances, line running or still, weak link or no, spring, gravity
or muscle powered, radios or how did you know and like that.

Bob Johnson

Dave Martin wrote:
>
> To any club using plasma ropes in place of steel.
>
> Having read the benefits of this type of rope, several
> UK clubs are interested in its use. One major obstacle
> to this, is cutting it during a launch, in the event
> of an emergency
>
> So far the best methods appear to be an axe an anvil
> type cutter.
>
> Any slight imperfections on scissor, guillotine and
> even the axe methods of cutting mean the rope does
> not get completely cut through. Even though the equipment
> cuts steel succesfully.
>
> Various methods such as hot wire and laser beams have
> been suggested, but with the way members treat club
> equipment I suspect the life of such things would be
> minimal.
>
> What emergency cutting methods for plasma rope do those
> who use it employ?
>
> Thanks in anticipation
>
> Dave Martin
>
>

[Bill Higdon]

How about a chunk of "Det. cord" in a circle or two with the Plasma rope
running through the center. Use a "pull" type of initiator to trigger
the Det. cord.
Bill Higdon
Bill Daniels wrote:
> Bob, you need to get some of this stuff and play with it. It doesn't cut
> the way metal does - in fact, it's the preferred body armor for knives and
> penetrating weapons.
>
> The people who work with this stuff all the time use electrically heated hot
> blades. They cut through it like it isn't even there.
>
> Bill Daniels
>
> "Bob Kuykendall" > wrote in message
> om...
>
>>Earlier, "Bill Daniels" > wrote:
>>
>>
>>>Why should a hot blade be fragile?
>>>The winch engine starting battery has a
>>>lot of power to heat a robust blade very
>>>quickly.
>>
>>I would definitely look askance at a system that required electricity
>>to cut the cable, and I think that most certification authorities
>>might also. I prefer my emergency systems to be powered by gravity,
>>strong springs, or if necessary percussion-lit pyrotechnics.
>>
>>
>>>You only need to get the
>>>blade to Spectra's 265F melting
>>>point - far below the blades
>>>melting point.
>>
>>I'd tend to believe that you need to heat the blade to about twice or
>>three times that - to account for the fact that you might be trying to
>>cut the cable as it is running in or out, and so the blade is
>>transferring heat to a pretty large volume of cable. Also, you'd want
>>to cut the cable as fast as possible. This might be a neat idea if it
>>were heated by exhaust from the winch engine...
>>
>>My preference would be for a sharp guillotine, for which the blade can
>>pivot slightly to account for minor misalignments between the arm axis
>>and the plane of the anvil. I'd try an anvil made of a 2" by 6" piece
>>of MDF (medium density fiberboard) to be renewed after each slice. In
>>testing, I'd look for 25 cuts out of 25 tries.
>>
>>Just my few ill-formed thoughts on the matter.
>>
>>Thanks, and best regards to all
>>
>>Bob K.
>
>

[W.J. \(Bill\) Dean \(U.K.\).]

There was a fatal accident in the U.K. when the glider being launched got
the launching wire over a wing. The guillotine was fired by the winch
driver, but failed to cut the wire (which was of course being pulled out by
the glider). It is not certain that cutting the wire would have saved the
pilot, but he had little chance with it uncut.

As a consequence of this accident we are very aware in the U.K. of the
necessity for a reliable method of cutting the cable. The guillotine was
re-designed, and they are now regularly serviced and tested in accordance
with a laid-down schedule.

So the answers to your question are; yes, the winch driver could see the
problem, the guillotine failed to cut the wire.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.

>
> "Bob Johnson" > wrote in message
> ...
>
> <snip>
>
> Wondering about guillotines in general, I know it's always good to have
> one, but has anyone in earshot actually used one? If so, what were the
> circumstances, line running or still, weak link or no, spring, gravity
> or muscle powered, radios or how did you know and like that.
>
> Bob Johnson
>